duct detectors interlock wiring

[rayertz]

in an industrial setting, does interlock wiring for duct detectors installed in the duct for air supply houses shut down have to be hard wired from the duct detector to the ASH controls or is devicenet suitable?

We are using device net from the duct detector to the ASH control system for the ASH shut down circuitry. In event of smoke the duct detector trips, sends an alarm to the fire alarm control panel and central security and shuts the ASH down.

The fire alarm contractor is telling me it must be hard wired.

 

[rlundsrud]

Yes, it must be a hardwired interlock, typically wired to the VFD/starter or if there is a BAS system it is part of the safety interlock string. It is only required for air handlers that exceed 3500 cfm.